This week's dispatch from the commute comes in an e-mail from David James of Sublimity.

Subject: Biker noise. (As the neighbor of a Harley-Davidson owner, I like where this one's going).

"Hey, Joe," James writes. (Hey, back at ya).

"I've never been able to understand the mentality of someone who apparently thinks 'Gee, it's a nice day - think I'll go out and deafen a few people!' I'm talking about some Harley riders, of course (not all choose to have their bikes in window-rattling, eardrum-shattering mode)."

Actually, that's one of the main reasons to own a Harley, or so I've been told by friends who have them. So, the school of thought seems to be, why own an expensive, born-in-the-USA motorbike if you can't let everyone within a block or two know you own one?

Different strokes, I guess.

Anyway, back to David.

"I guess these people think that it takes a REAL MACHO dude to handle something that freaking loud so naturally, people will think they're the ultimate in sexy power. I happen to view them as the ultimate in ego-deprived pinhead, but that's just my humble view."

Okaaay. Well, I guess it's better to let a little of that steam off here than on the road. I'm suddenly trying to shake images of bandannas and handlebar mustaches from my head. Maybe it's a good time to visit the festering debate of hair bands vs. grunge bands. (I'm siding with grunge).

Or I could just get to David's question.

"My question is - isn't there some sort of law in Oregon about how loud a motor vehicle can be? I know their used to be, and that it was enforced in Portland when I was young. If there is such a law, why isn't it enforced these days?"

There is such a law in Oregon. The standard, set out in Department of Environmental Quality rules, is 94 decibels within a 25 foot radius for motorcycles built before 1976 and 89 decibels for models after that.

For the sake of comparison, a typical rock concert is 110 decibels and a jet engine is 140 decibels. A food blender 3 feet away emits about 90 decibels.

Sure, some mornings, when my neighbor goes roaring down the street on his Harley, shaking me from slumber at 5:30 a.m., it sounds like a space shuttle is launching from my front yard. But I'm assuming it's just perception - and me being a little crusty.

Then again, there's a chance that he's illegally altered his hog's muffler, said Steve Garets, director of the state's Team Oregon motorcycle education program.

"Motorcycles come from the factory stocked with parts within specifications of our noise laws," Garest said. "But a lot of times, riders will put aftermarket pipes on" that create more noise.

Many motorcyclists argue that sound saves lives. In Oakland, Calif., the issue of officer safety was behind last month's decision by Oakland police to equip their Harleys with louder tailpipes.

"That's nonense," Garets said. "There's no evidence to support that. The sound is going back and getting lost behind them."

Unless a peace officer is carrying a sound meter (which isn't standard issue on patrol), it can be hard to ticket a motorcyclist for breaking the decibel barrier, said Oregon State Police Lt. Gregg Hastings. At the same time, there are laws against unnecessarily revving an engine and troopers can sometimes make a judgment call if they notice aftermarket parts on a bike.

"Like a lot of things," he said, "it depends on the situation."

Police say they do what they can to investigate vehicle noise complaints and to cite someone who is obviously operating a motorcycle beyond the limits of the DEQ rules. At times, DEQ says it has gone to a neighborhood or traffic stop at the request of an officer to test noise levels on a vehicle.

You'd think DEQ wouldn't allow motorcycle owners to buy new registration tags if they failed a noise test every two years. But here's the thing: Motorcycles are exempt from regular environmental testing in Oregon.

So, to answer your question David: Yes, there a rules. And yes, the cops are listening, sometimes ticketing motorcycle owners for violating them. But it can be a tough call for police.

Now you've got me thinking about shopping around for a noise meter to measure the morning roar on my street.